Hi amber, As soon as mine was able to eat 2 pinks I moved her up to fuzzies. As a test look at the widest part of her body, add half of that again, and thats the largest size that you can feed. In my experience, which is little admittedly, they can take food items much larger than we give them credit for.
And how do you feed pinkies? Defrost them in warmish water, wait till the heads soft as it's the last part to defrost, then dry it off. Take you snake and place it in a feeding container (bucket, critterkeeper etc etc). I use feeding tongs, so grab the back legs with them and jiggle it about in front of her and in no time at all you'll have one snake constricting/eating a mouse.
I love the part where she gets her head really close to the mouse and slowly shapes her body into an 'S' ready for the strike, hehe. :grin01: